RESUMO
Here we describe the synthesis and characterization of a new class of dinuclear PtII complexes with blue phosphorescence. Bulky N-heterocyclic carbene and tethered bridging ligands were employed to suppress photo-induced structural changes and to improve thermal stability of the complexes. These complexes show mixed 3 IL/3 MLCT blue emission (≈460â nm) with emission quantum yields of up to 0.95, emission lifetimes of as low as 1.3â µs and radiative decay rate constants of up to 7.3×105 â s-1 in 4â wt % doped PMMA films; the latter is attributed to a 1 MLCT excited state having high metal character (resulting in a large SOC) and a large transition dipole moment, based on DFT calculations. Phosphor-sensitized blue hyper-OLEDs with Commission Internationale de L'Eclairage (CIE) coordinates of (0.13, 0.12) showed a maximum EQE of 23.4 % with a full-width-at-half-maximum of 18â nm and a LT50 >250â h at an L0 of 1000â cd m-2 .